Windows RT, the name Microsoft has given to Windows running on the ARM processors, will have two environments, a Windows Classic environment and a Metro environment for apps. However, Windows on ARM prohibits any browser except for Internet Explorer from running in the privileged “Windows Classic” environment.

Technically, Mozilla could release a version of Firefox for Windows 8’s new Metro interface, said Asa Dotzler, a Mozilla spokesman. But that browser would be crippled on Windows RT.

Google has joined Mozilla in its desire to permit full-fledged browsers other than Internet Explorer on Windows RT. Google makes the popular Chrome Browser. “We share the concerns Mozilla has raised regarding the Windows 8 environment restricting user choice and innovation,” replied Google to a query by C/Net. Microsoft declined to comment on Mozilla’s stance.

With Windows RT, Microsoft appears to be aiming for an operating system more in the style of iOS than Windows on the x86 chips. Microsoft wants to build tablets that compete with iPads. Windows RT can only be obtained preinstalled on hardware and it can only install software updates from the Windows Store. Third-party browsers are apparently not welcome.